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Sega Master System 1 - Jailbreak

  • 31-05-2025 05:42PM
    #1
    Registered Users, Registered Users 2 Posts: 8,185 ✭✭✭


    Ok, hyperbolic title aside, it's a common observation that despite outputting native RGB, the Sega Master System 1 has a very obvious jailbar effect on its output. It's just inherent to the Sony CXA chip that processes the signals, so there's no quick & easy way to fix it. There is though, the option of fitting an RGB bypass board to the console, bypassing the Sony CXA chip altogether, and using something that processes the signals in an improved fashion….so let's do that!

    1748707066588.jpg

    ^^ The console in question, the Model 1 Sega Master System. Love the styling, so very 80's. It's obviously the better version of the Master System, complete with card reader (though I do have more of a nostalgic connection to the Model 2, as that's the one I owned back in the day.)

    1748707066576.jpg

    ^^ A quick power up check to ensure I'm dealing with a working machine. It powers up to a green light…

    1748707066568.jpg

    ^^ I don't know if it'll come through in an embedded image, but the vertical jailbars are very significant.

    1748707066558.jpg

    ^^ Same again here, and there's a wavy/oscillating pattern that's static in the lines on this level.

    1748707066542.jpg

    ^^ Again here, just incase they're hard to spot (not sure how they'll look until I post the thread.)

    1748707066536.jpg

    ^^ Ok, console open, the patient on the table for surgery.

    1748707066522.jpg

    ^^ Heatsink removed, and mainboard now sitting free.

    1748707066491.jpg

    ^^ RF Modulator removal, this gives us a nice area to affix the bypass board into, and obviously RF isn't ever getting used these days.

    1748707066466.jpg

    ^^ I figured while I'm in here, I'd remove all the original capacitors (they may be in spec, but they're nigh on 40 years old at this point, so a fresh set will keep things running happy for another good few years!)

    1748707066452.jpg

    ^^ All capacitors now replaced with Panasonic & Rubycon's of equivalent values.

    1748707066446.jpg

    ^^ Another quick test after replacing the caps, just to ensure everything is as it should be. The system powers up, the built-in game boots, and it all looks good.

    1748707066426.jpg

    ^^ First thing is first, we need to sever the RGB & Sync lines going to the Multi-Out. These lines are now redundant, as we will be feeding the newer, better handled signals to the multi-out ourselves. The above shows where I cut the traces for two of the RGB signals (can't remember which two.) This mainboard version has the traces on the top side of the board, instead of the bottom as shown in many tutorials, so this way is a little more delicate.

    1748707066418.jpg

    ^^ The other signal of the three RGB lines now cut too.

    *** I forgot to show cutting the trace for the Sync line on the underside of the board.***

    1748707066404.jpg

    ^^ This is the RGB Bypass I'll be using. I bought the version on OSH Park, which I'll keep as a reference, but with some blippidy blops I was able to adapt the files to have my own printed by PCBway (hence the blue and not the purple of OSH Park.) It's a matter of adding on the 7314 video chip, some caps, some resistors, and that's it.

    1748707066397.jpg

    ^^ It's designed to mount in where the RF Modulator was. I lay down a bit of kapton tape as an insulator, but the bottom of the bypass doesn't look like it's a risk anyway.

    1748707066389.jpg

    ^^ I solder three resistor legs into the ground anchors for the RF Modulator….

    1748707066375.jpg

    ^^ And the designer of the PCB has lined up the anchor points so the resistor legs solder directly to them….it's rock solid like this. I've also removed the three SMD capacitors as the cable I'm using has the capacitors inside the cable, so the ones here aren't needed. So instead of using the RGB Outputs, you simply use the capacitor input pads as the video outputs.

    1748707066368.jpg

    ^^ 5v fed into the bypass board from the modulator power point, and the three RGB lines are tapped off the board and fed into the RGB inputs on the bypass too.

    1748707066347.jpg

    ^^ Sync now fed to the board. The RGB output lines are now in place and fed directly to the multi-out as per the tutorials (though the scart cable I'm using is wired for sync off a different pin on the multi-out, so I changed the white wire to that point later on.)

    1748707066335.jpg

    ^^ All wired up, and ready to test…

    1748707066322.jpg

    ^^ Hmm, it's looking very sharp…no jailbars in the whites of the Sega logo anyway…

    1748707066311.jpg

    ^^ Aw man….the image is SSOOOO much better. The colours are so punchy in person, the image is super sharp, and very importantly, the jailbars are all but gone!

    1748707066258.jpg

    ^^ That ugly oscillating pattern is gone too….it looks great.

    1748707066246.jpg

    ^^ Reassembly time, I clean off the heatsink contact area, and put some fresh MX-2 in place, so the heatsink should transfer heat into the heatsink more efficiently now.

    1748707066239.jpg

    ^^ Job done.

    1748707066232.jpg

    ^^ Beauty shot to close 😎



Comments

  • Registered Users, Registered Users 2 Posts: 9,294 ✭✭✭MrVestek


    You really…
    (••)
    ( •
    •)>⌐■-■
    (⌐■_■)

    Mastered that System…

    YYYYYYYEEEEAAAAHHHHHHH….



  • Registered Users, Registered Users 2, Paid Member Posts: 4,447 ✭✭✭KeRbDoG


    Nice - always thought the design and the 'diagram' on the console looked great.

    In that model of Master System, is the built-in game a ROM chip that could be replaced?



  • Registered Users, Registered Users 2, Paid Member Posts: 37,208 ✭✭✭✭o1s1n
    Master of the Universe


    To my shame, I'm only now realising that is a diagram and the triangle isn't a button!

    Never owned one and always just assmed the trinagle and square were buttons (you know those flat type ones you get under a plastic display)

    I now see the power button is on the bottom left. That's absolutely gas. 😂



  • Registered Users, Registered Users 2 Posts: 8,185 ✭✭✭Inviere


    The built in game will be built into the bios chip. Fully replaceable with an eprom yep, but not socketed.



  • Registered Users, Registered Users 2 Posts: 19,021 ✭✭✭✭McDermotX


    We had one in the family home way back when it came out years ago, and obviously very good memories of the times - Out Run, Afterburner, Black Belt, Fantasy Zone, My Hero, Choplifter etc etc………….BUT, one of my most vivid memories of it (besides one of the buttons not working for Player 2) was when during one of the marathon playing sessions, one of the brother's mates was up near the end of Alex Kidd in Miracle World and needed to pause the game before his final assault.

    None of this hit the start button on the pad to pause the game lark, it's that pause button on the main unit - over he goes to the console on the ground - and hits the Reset button. Funniest meltdown I've ever witnessed.



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  • Registered Users, Registered Users 2 Posts: 8,185 ✭✭✭Inviere


    Funnily there's a nice mod you can do to add Pause functionality to the controllers, but I don't want to drill the small hole in the controllers for a button!



  • Registered Users, Registered Users 2 Posts: 19,021 ✭✭✭✭McDermotX


    Brilliant ! No surprise people looked into it alright 😂Excellent work as always Inviere



  • Moderators, Category Moderators, Computer Games Moderators Posts: 53,966 CMod ✭✭✭✭Retr0gamer


    There's something so nice about that master system power base and how it looks. Much nicer than the master system 2.



  • Registered Users, Registered Users 2 Posts: 8,185 ✭✭✭Inviere


    The Model 2 is extremely basic in comparison, and a lot more generic. The model 1 has a unique "of its time" old school look. That said, the Model 2 is the one I knew back when.



  • Registered Users, Registered Users 2, Paid Member Posts: 37,208 ✭✭✭✭o1s1n
    Master of the Universe


    Any of you guys ever have the Sega cards that go with the model 1 Master System / Model 1 power base converter?

    Another thing I've never actually seen in person. I see they look to be exactly the same size as the PCE HUCards.



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  • Registered Users, Registered Users 2 Posts: 8,185 ✭✭✭Inviere




  • Moderators, Category Moderators, Computer Games Moderators Posts: 53,966 CMod ✭✭✭✭Retr0gamer


    Jeremy Parish went through them on his Segaiden series. Most of them are very early games for the system and were quickly phased out. I used to go to a childminder whose son had a master system and of course barely let us touch it but do remember seeing him play Ghost House on card format. Apparently they are the same tech as used by Hu cards.



  • Registered Users, Registered Users 2 Posts: 19,021 ✭✭✭✭McDermotX


    Had a few cards but long lost to the mists of time, the aforementioned Ghost House, Teddy Boy, Super Tennis, My Hero, Hang On etc off the top of my head. Didnt have the 3D Glasses, but it also used an adapter requiring the card slot - part of the reason they were only good for the original base unit. Exactly like HuCards in operation alright, but very much seen as 'the budget range' of games back then as they could only address up to 32KB IIRC

    Old Mastertronic distribution flyer attached



  • Registered Users, Registered Users 2 Posts: 1,607 ✭✭✭BGOllie


    I've a few here , Ghost House, Spy vs Spy and Hang on. They're cool pieces but hard to display unless you've them CIB .



  • Registered Users, Registered Users 2, Paid Member Posts: 1,069 ✭✭✭Brian CivilEng


    Did many people have the Master System here? I remember in school all us Nintendo owners wondering if it actually existed. It was always there in the catalogue opposite the Nintendo but never seen one in person until recently. One guy said his cousin had one but that was it.
    I remember the MegaDrive already being out by the time I got my Nintendo.



  • Registered Users, Registered Users 2 Posts: 8,185 ✭✭✭Inviere


    Yeah I had a Model 2 around the NES time, maybe a little after it. Alex Kidd built in, still love the game.



  • Registered Users, Registered Users 2, Paid Member Posts: 37,208 ✭✭✭✭o1s1n
    Master of the Universe


    The Master System was actually outselling the NES in Europe up until 1993 believe it or not. It was the console that broke Europeans out of their micro computer preference of the 70s and 80s.



  • Registered Users, Registered Users 2, Paid Member Posts: 1,069 ✭✭✭Brian CivilEng


    I keep seeing that quoted but I don’t believe it. Master System was popular in UK and Germany apparently but definitely not here.



  • Registered Users, Registered Users 2, Paid Member Posts: 8,000 ✭✭✭The_B_Man
    Something about sandwiches


    One childhood friend had one. He was the only one I knew to have one. Got a loan of it off him for a while. I had a megadrive at the time so I suppose I didn't look at it as fondly, due to that.



  • Registered Users, Registered Users 2, Paid Member Posts: 37,208 ✭✭✭✭o1s1n
    Master of the Universe


    What years are you talking about? You might be a little young to remember any part of the Master Systems 80s popularity if your gaming memories start in the Megadrive era.



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  • Registered Users, Registered Users 2, Paid Member Posts: 1,069 ✭✭✭Brian CivilEng


    My memory was that until 1990 or so it was all about the c64, with a handful of Spectrums or Atari 2600s. But Christmas 1990 the Nintendo started taking over.



  • Moderators, Category Moderators, Computer Games Moderators Posts: 53,966 CMod ✭✭✭✭Retr0gamer


    Master system was definitely more successful here in the late 80s. The NES would gain some popularity in the early 90s as Mattel would liquidate there stock when Nintendo took over distribution and then Nintendo would market it as a budget console for people that couldn't afford the SNES. But the master system definitely kept pace with NES sales.



  • Registered Users, Registered Users 2, Paid Member Posts: 37,208 ✭✭✭✭o1s1n
    Master of the Universe


    Thats it really. I remember my cousin got a NES around 1990 and then a Snes fairly soon afterwards. I was playing the NES alongside my Megadrive for quite a few years through the 90s.

    We were both a bit young to have experienced the late 80s Master System days.



  • Moderators, Category Moderators, Computer Games Moderators Posts: 53,966 CMod ✭✭✭✭Retr0gamer


    The first big push of the NES was 1991 with the release of Mario 3. Nintendo had taken over distribution of the NES in 1990 I think. Before mario 3 there was very little nintendo marketing in europe although I remember a big push for Kirbys Adventure.



  • Registered Users, Registered Users 2, Paid Member Posts: 1,069 ✭✭✭Brian CivilEng


    Been reading up on the sales. Even in the big markets the Master System had a very short life, launched in Europe in ‘87 and the Megadrive arrived in ‘89. I can’t remember seeing a Megadrive that early mind.

    I still don’t believe it sold anywhere near as much in Ireland as the Nintendo mind. In the second hand market i never saw that many Master System titles, which NES were ten a penny at one stage. Only saw my first Master System 1 in person on a visit to RMC The Cave in England last year



  • Moderators, Category Moderators, Computer Games Moderators Posts: 53,966 CMod ✭✭✭✭Retr0gamer


    Megadrive didn't arrive until the tail end of 1990 in Europe and the master system continued on as a budget console, same as the SNES until 1996. I think the NES stopped about 1994



  • Registered Users, Registered Users 2, Paid Member Posts: 1,069 ✭✭✭Brian CivilEng


    That tracks with my memory, first Megadrive I saw was probably in 1991. But as I said before, never actually saw a Master System.

    I remember seeing the Master System in catalogues but it not being in the shop.



  • Registered Users, Registered Users 2, Paid Member Posts: 4,447 ✭✭✭KeRbDoG


    I saw a few Master Systems, prob the same amount of NES consoles when they had been out a few years - 'out in the country' though, there was still a lot of C64 and CPC464 computers going at the same time



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